大跨度屋盖结构等效静力风荷载方法及应用

结构风致振动是控制大跨度屋盖结构设计的主要因素。大跨屋盖结构模态密集,风致振动有多模态参与并受模态交叉项影响的特性,这给建立大跨度屋盖结构等效静力风荷载的计算方法带来了很大的困难。本文基于计算共振分量的修正SRSS法,将LRC法和考虑模态耦合系数的惯性风荷载法相组合来表示等效静力风荷载。本文的方法能考虑模态之间相互耦合的情况,给出的等效静力风荷载具有明确的物理意义。最后将该方法运用于一个实际工程,检验了计算方法的精度。计算结果表明,本文方法和CQC法得到的响应值非常接近,最大误差约为3%,相对而言SRSS法的计算误差较大。

Equivalent static wind loads of large-span roof structures

Wind effects typically controls the design of large-span roofs.Based on the modified SRSS method,an equation for equivalent static wind loads combining mean,background and resonant components,is derived.In the equation,the background and resonant components are computed with the LRC method and the equivalent inertia force method considering modal coupling effects,respectively.The equivalent static wind loads given by the proposed method can consider modal coupling effects and have explicit physical rationale.At last,the method is applied in the roof structure of Shanghai South Railway Station to investigate its accuracy.The results obtained by the new method,which have sufficient accuracy with a maximum error of 3%,are close to ones calculated using CQC method.It also shows that SRSS method is not suitable for large-span roof structure.